Two-point normalization for reducing inter-laboratory discrepancies in δ17O, δ18O, and Δ′17O of reference silicates

Journal of Analytical Science and Technology

Table 2 δ¹⁷O and δ¹⁸O values of the waters and silicates measured in this study

Sample	Number of analysis	δ¹⁷O_VSMOW^a	1SD^b	δ¹⁸O_VSMOW^a	1SD^b	δ'¹⁷O_VSMOW-SLAP^c	δ'¹⁸O_VSMOW-SLAP^c	δ¹⁷O_VSMOW-SLAP^d	δ¹⁸O_VSMOW-SLAP^d	Δ'¹⁷O^e	1SD^b
Waters
VSMOW	11	0.000	0.030	0.000	0.057	0.000	0.000	0.000	0.000
SLAP	8	-29.148	0.083	-54.477	0.155	-30.148	-57.100	-29.698	-55.500
Silicates
UWG2 garnet	35	3.012	0.034	5.802	0.054	3.066	5.897	3.070	5.914	-0.007	0.011
NBS28 quartz	12	4.880	0.037	9.328	0.071	4.961	9.464	4.974	9.509	0.006	0.009
San Carlos olivine	9	2.835	0.046	5.436	0.080	2.885	5.526	2.889	5.541	0.008	0.011
Stenvs Klint Flint Standard	4	17.153	0.115	32.967	0.217	17.333	33.062	17.484	33.615	-0.077	0.012
Khitostrov Rock Standard	4	-12.947	0.181	-24.230	0.325	-13.282	-24.999	-13.194	-25.478	-0.046	0.009
Natural rocks
Basalt glass	45	2.903	0.051	5.584	0.095	2.954	5.676	2.958	5.692	-0.002	0.010
Obsidian	127	4.384	0.075	8.404	0.144	4.459	8.531	4.469	8.568	-0.004	0.013
Working standard (O₂)		-5.071		-9.618		-5.181	-9.852	-5.168	-9.803

^aδ-values are expressed as per mil relative to Vienna Standard Mean Ocean Water (VSMOW)
^bStandard deviation (SD) means an external reproducibility for each analyses
^cDelta prime (δ') is defined as 10³×ln(δ^xO+1) by Miller (2002). The VSMOW-SLAP scaling factor (1.019) is applied to linearized delta prime values
^dδ-values are obtained from linearized delta values after normalization by the scaling factor
^eDeviation of ¹⁷O/¹⁶O ratio of sample is estimated as: Δ'¹⁷O = δ'¹⁷O_VSMOW-SLAP − 0.5278×δ'¹⁸O_VSMOW-SLAP + 0.040